Blackboard-compasses.



F. C. HULSE & L. S. UPHOFF.

BLAGKBOARD GOMPASSBS.

APPLIQATION FILED MAR. 31, 1914.

Patented Dec. 15,1914.

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- unrrnn STATES PATENT orrron.

FRANK C. HULSE AND LESLIE S. UPI-IOFF, OF SCHENEOTADY, YORK.

BLAO'KBOARD-GOMPASSES.

. Specification of Letters Patent.

Patented Dec. 15, 1914.

Application filed. March 31, 1914.. Serial no. 828,578.

To all whom it may concern:

Be it known that we, FRANK. C. HULSE and LESLIE S. UPHOFF, citizens of the United residingat Schenectady,in the county of Schenectady and State of New York, have invented new and useful Improvements in Blackboard-Compasses, of which the following is a specification.

The invention relates to a compass, and

more particularly. to the class of drafting compasses adapted for use in connect on with blackboards in schools, colleges or elsewhere.

The primary object of the invention is the provision of a compass wherein the legs thereof are constructed to permit the projecting of the marking material and also to permit the fixed or anchoring point to be held firmly to the blackboard or other marking surface. l

Another object of the invention is the provision of. a compass of this character wherein the marking material when projected Will be firmly held against slipping action Within the leg of the compass.

A further object of the invention is the provision of a compass wherein the fixed or anchoring point revolubly supports the leg holding the marking material so that the compass can be conveniently manipulated without the anchoring or fixedpoint mutilating the Writing surface of the blackboard or the like when the instrument is in use.

A still further object of the invention is the provision of a compass which is simple in construction, novel in form, reliable and efficient in its purpose, and inexpensive in manufacture.

With these and other objects in view, the

inventionconsistsin the construction, combination and arrangement of parts as will be hereinafter fully described, illustrated in the accompanying drawing, and pointed out in the claims hereuntoappended.

In the drawing :Figure l is a side elevation of a compass constructed in accordance with the invention. Fig. 2 is an enlarged fragmentary side elevation of one leg of the compass, the same being partly in section. Fig. 3 is a fragmentary vertical sectional view on an enlarged scale of the other leg of the compass. Fig. 4 is a fragmentary side elevation on an enlarged scale of a modified form of the leg of the compass.

Similar reference characters indicate corresponding parts throughout the several views in the drawing.

Referring to the drawing in detail, 10 and 11 designate therespective legs of the compass, which are swingingly connected together by means of a pivot 12 so that the legs can be spread apart or broughtqclose together as the occasion may require in the use of the compass. The leg 10 at its free end portion forms a'socket to receivea stick G of marking material and is provided with oneormorelongitudinal slots L so that the said free-ends of the legs can expand and contract for the freeing or clamping of the stick C therein. .Slidably fitted on-the leg 10 is a clamping sleeve T having a slightly outwardly flared, end D which co-acts with I an enlargement U at the free end of the leg 10 to compress the same into clamping relation'to the stick 0 held within the leg. The opposite orinner end of the sleeve T is formed with a cam edge N which is adapted to engage a pin P fixed in the leg 10 so that on the turning of the sleeve T the same will be moved onto the enlargement U for compressing the free end thereof against the stick G. On turningthe sleeve T in the reverse direction the same will work off ofthe enlargement U at the free end of the leg 10, permitting it to expand for releasing the stick C so that it may be removed or adjusted as may be required.

Slidably fitted within, the leg 10 rearwardly of the stick G is an ejector pin R which has vfitted therein a finger lug K projected through an elongated slot S formed in the leg 10 so that the pin R can be manually moved, which is designed to act upon the stick C to project it from the leg 10 when the free end of the latter is expanded, and in this manner the said stick can be readily adjusted orremoved from the leg 10 of the compass.

The other leg ll of the compass is socketed to receive the reduced stem W of an anchoring tip Z which carries in its free end a rubber anchoring point- V which is fixed'therein in any suitable manner, it being understood of course that the point V may be made from other material if found desirable. The stem Wv of the tip Z is formed with an annular slot G into which projects a retaining pin Y, the latter being mounted in the leg ll, and in this manner the said tip is swiveled in the latter,

portionofv-the oompas s Will-revolye thereon. In F 4 there is shown a slight modifi cation of one of the legs of the compass Wheresconstruction andinannep of aseoffthe device ifilllhe elearly nhderstood; arid therefore a "more extended explanation has gloeen onlitted.

1. Ina-compass, a leg having a split end,

in the leg 13 has fixed thereto the extensionma s'leeve slidably and rotatably supported on let of "a ehallpholder comprising a barrels-O which is angular-1y disposed With respect to hiq rmedw ith 0 60 more l ts E longitudinally disposed therein, -and into this tube; is fitted the stick *Gof suitable Writing material or chalkl; A r j {Formed in the barrel l O is a e'am slot B,

While mounted in-the tubellisa fingerlmob H *vsfhih projeets'througlrthe cam slot B- and is guided therein to project or retract the tribe A withontorwithin the barrel, and in "this manner thesplit' endof "the tube isTeXp ancle d or-"compressed "for the freeing ohelani'pingf of the chalk therein; It is of ou'rse to understood that "the stick C is of V gre ater Cross} seet'ional d l'an'ieter" than the inner-diaineterof the tribe Azso' that when the stick is inserted thereinit will expand the split end" thereof so that when the "said tilbeis contracted Within the loarflrel thefsplit ehd WillEbe ornpressed for the clamping of the ehalkln'thetube. p I a m Fro f h'' e oi it 'rfihp'u wattle wema t a n. H

itheit-split leg and having a carnmed-inner I edge, a pin fixed in the end and Working I the leg 13, and has fitted therein a tube A a sleeve' slidablyjandrotatahly supported on the sp litll'eg and having a *c'ammed inner.

aana ia;endrkin against "the cam edge" of" the sleeve, a'n eh large nent farmed oaths split end." (11.211116 legend adapted to 'beitfai ersedby the sleeve pr comp1-essingfihesplit. e dpf thefleggari ejector; pin slidably' fittedwithin 'the leg;

and means carried 'by-the 'p'iIi'an'd projeeteq (ixteriorlypf the leg moVing Said pie;

I ftestim three in presence of two Witnesses.

FRANK O. HULsEy= i v E IE nPH-om filler BPPMQNP- 

